The importance of the time response of Electrochemical Concentration Cell (ECC) ozone sondes for measurements of tropical upper tropospheric and lower stratospheric ozone

Accurate measurements of ozone in the upper tropical troposphere and lower stratosphere (UTLS) are challenging for most measuring systems, yet of great importance for the understanding of the chemical and dynamical processes in this region.Balloon-borne observations using Electrochemical Concentration Cell (ECC) ozone sondes are the most widely used in situ technology to measure vertical profiles of ozone in networks such as the Southern Hemisphere ADditional Ozonesondes (SHADOZ) network of tropical and subtropical ozone sonde stations.The tropical upper troposphere and the layers of near-zero ozone within the ozone hole are most sensitive to processing and preparation variations that may affect the accuracy and possibly trend estimates of ozone in low ozone regions. It is now appreciated that the complex chemistry within the ECC used to detect ozone exhibits two different time constants (&#964;fast&#8776;20 s, &#964;slow&#8776;25 min), which modify the response of the ECC during a profile. Although not well understood, the chemistry of the slow reaction is likely to represent what has conventionally been assumed a constant &#8220;background current&#8221;. The fast reaction causes some delay in the response of the ECC to changes in the vertical profile of ozone. Here we show how correcting for both improves the estimate of the lowest ozone concentration in the upper troposphere as well as the steepness of the gradient in the transition into the stratosphere. The steady state bias, which describes the contribution of the slow reaction, is the largest source of uncertainty overall; the response time of the fast reaction dominates the uncertainty in the region of the sharp gradient of ozone above the tropopause.

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Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 field experiment

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-7667-2015 ◽

2015 ◽

Vol 15 (13) ◽

pp. 7667-7684 ◽

Cited By ~ 13

Author(s):

Fuqing Zhang ◽

Junhong Wei ◽

Meng Zhang ◽

K. P. Bowman ◽

L. L. Pan ◽

...

Keyword(s):

Power Law ◽

Gravity Waves ◽

Lower Stratosphere ◽

Potential Temperature ◽

Shear Instability ◽

Aircraft Measurements ◽

Upper Troposphere ◽

Airborne Measurements ◽

Wide Range

Abstract. This study analyzes in situ airborne measurements from the 2008 Stratosphere–Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS). The focus is on the second research flight (RF02), which took place on 21–22 April 2008. This was the first airborne mission dedicated to probing gravity waves associated with strong upper-tropospheric jet–front systems. Based on spectral and wavelet analyses of the in situ observations, along with a diagnosis of the polarization relationships, clear signals of mesoscale variations with wavelengths ~ 50–500 km are found in almost every segment of the 8 h flight, which took place mostly in the lower stratosphere. The aircraft sampled a wide range of background conditions including the region near the jet core, the jet exit and over the Rocky Mountains with clear evidence of vertically propagating gravity waves of along-track wavelength between 100 and 120 km. The power spectra of the horizontal velocity components and potential temperature for the scale approximately between ~ 8 and ~ 256 km display an approximate −5/3 power law in agreement with past studies on aircraft measurements, while the fluctuations roll over to a −3 power law for the scale approximately between ~ 0.5 and ~ 8 km (except when this part of the spectrum is activated, as recorded clearly by one of the flight segments). However, at least part of the high-frequency signals with sampled periods of ~ 20–~ 60 s and wavelengths of ~ 5–~ 15 km might be due to intrinsic observational errors in the aircraft measurements, even though the possibilities that these fluctuations may be due to other physical phenomena (e.g., nonlinear dynamics, shear instability and/or turbulence) cannot be completely ruled out.

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Characterising the seasonal and geographical variability in tropospheric ozone, stratospheric influence and recent changes

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-3589-2019 ◽

2019 ◽

Vol 19 (6) ◽

pp. 3589-3620 ◽

Cited By ~ 9

Author(s):

Ryan S. Williams ◽

Michaela I. Hegglin ◽

Brian J. Kerridge ◽

Patrick Jöckel ◽

Barry G. Latter ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Tropospheric Ozone ◽

Radiative Forcing ◽

Lower Stratosphere ◽

Climate Model ◽

Stratospheric Ozone ◽

Data Availability ◽

Ozone Production ◽

Upper Troposphere ◽

The World

Abstract. The stratospheric contribution to tropospheric ozone (O3) has been a subject of much debate in recent decades but is known to have an important influence. Recent improvements in diagnostic and modelling tools provide new evidence that the stratosphere has a much larger influence than previously thought. This study aims to characterise the seasonal and geographical distribution of tropospheric ozone, its variability, and its changes and provide quantification of the stratospheric influence on these measures. To this end, we evaluate hindcast specified-dynamics chemistry–climate model (CCM) simulations from the European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model and the Canadian Middle Atmosphere Model (CMAM), as contributed to the International Global Atmospheric Chemistry – Stratosphere-troposphere Processes And their Role in Climate (IGAC-SPARC) (IGAC–SPARC) Chemistry Climate Model Initiative (CCMI) activity, together with satellite observations from the Ozone Monitoring Instrument (OMI) and ozone-sonde profile measurements from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) over a period of concurrent data availability (2005–2010). An overall positive, seasonally dependent bias in 1000–450 hPa (∼0–5.5 km) sub-column ozone is found for EMAC, ranging from 2 to 8 Dobson units (DU), whereas CMAM is found to be in closer agreement with the observations, although with substantial seasonal and regional variation in the sign and magnitude of the bias (∼±4 DU). Although the application of OMI averaging kernels (AKs) improves agreement with model estimates from both EMAC and CMAM as expected, comparisons with ozone-sondes indicate a positive ozone bias in the lower stratosphere in CMAM, together with a negative bias in the troposphere resulting from a likely underestimation of photochemical ozone production. This has ramifications for diagnosing the level of model–measurement agreement. Model variability is found to be more similar in magnitude to that implied from ozone-sondes in comparison with OMI, which has significantly larger variability. Noting the overall consistency of the CCMs, the influence of the model chemistry schemes and internal dynamics is discussed in relation to the inter-model differences found. In particular, it is inferred that CMAM simulates a faster and shallower Brewer–Dobson circulation (BDC) compared to both EMAC and observational estimates, which has implications for the distribution and magnitude of the downward flux of stratospheric ozone over the most recent climatological period (1980–2010). Nonetheless, it is shown that the stratospheric influence on tropospheric ozone is significant and is estimated to exceed 50 % in the wintertime extratropics, even in the lower troposphere. Finally, long-term changes in the CCM ozone tracers are calculated for different seasons. An overall statistically significant increase in tropospheric ozone is found across much of the world but particularly in the Northern Hemisphere and in the middle to upper troposphere, where the increase is on the order of 4–6 ppbv (5 %–10 %) between 1980–1989 and 2001–2010. Our model study implies that attribution from stratosphere–troposphere exchange (STE) to such ozone changes ranges from 25 % to 30 % at the surface to as much as 50 %–80 % in the upper troposphere–lower stratosphere (UTLS) across some regions of the world, including western Eurasia, eastern North America, the South Pacific and the southern Indian Ocean. These findings highlight the importance of a well-resolved stratosphere in simulations of tropospheric ozone and its implications for the radiative forcing, air quality and oxidation capacity of the troposphere.

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Transport of short-lived halocarbons to the stratosphere over the Pacific Ocean

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-1163-2020 ◽

2020 ◽

Vol 20 (2) ◽

pp. 1163-1181

Author(s):

Michal T. Filus ◽

Elliot L. Atlas ◽

Maria A. Navarro ◽

Elena Meneguz ◽

David Thomson ◽

...

Keyword(s):

Boundary Layer ◽

Lower Stratosphere ◽

Atmospheric Transport ◽

Convective Transport ◽

Transport Processes ◽

Lagrangian Model ◽

Convection Scheme ◽

Model Calculations ◽

Upper Troposphere ◽

Tropical Troposphere

Abstract. The effectiveness of transport of short-lived halocarbons to the upper troposphere and lower stratosphere remains an important uncertainty in quantifying the supply of ozone-depleting substances to the stratosphere. In early 2014, a major field campaign in Guam in the western Pacific, involving UK and US research aircraft, sampled the tropical troposphere and lower stratosphere. The resulting measurements of CH3I, CHBr3 and CH2Br2 are compared here with calculations from a Lagrangian model. This methodology benefits from an updated convection scheme that improves simulation of the effect of deep convective motions on particle distribution within the tropical troposphere. We find that the observed CH3I, CHBr3 and CH2Br2 mixing ratios in the tropical tropopause layer (TTL) are consistent with those in the boundary layer when the new convection scheme is used to account for convective transport. More specifically, comparisons between modelled estimates and observations of short-lived CH3I indicate that the updated convection scheme is realistic up to the lower TTL but is less good at reproducing the small number of extreme convective events in the upper TTL. This study consolidates our understanding of the transport of short-lived halocarbons to the upper troposphere and lower stratosphere by using improved model calculations to confirm consistency between observations in the boundary layer, observations in the TTL and atmospheric transport processes. Our results support recent estimates of the contribution of short-lived bromocarbons to the stratospheric bromine budget.

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In situ measurements of hydrogen cyanide in the upper troposphere/lower stratosphere during Arctic spring 2000

Journal of Geophysical Research Atmospheres ◽

10.1029/2001jd001033 ◽

2002 ◽

Vol 107 (D5) ◽

pp. SOL 47-1-SOL 47-6 ◽

Cited By ~ 2

Author(s):

A. A. Viggiano ◽

D. E. Hunton ◽

Thomas M. Miller ◽

John O. Ballenthin

Keyword(s):

Hydrogen Cyanide ◽

Lower Stratosphere ◽

In Situ Measurements ◽

Upper Troposphere

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Characterization of the long-term radiosonde temperature biases in the upper troposphere and lower stratosphere using COSMIC and Metop-A/GRAS data from 2006 to 2014

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-4493-2017 ◽

2017 ◽

Vol 17 (7) ◽

pp. 4493-4511 ◽

Cited By ~ 21

Author(s):

Shu-peng Ho ◽

Liang Peng ◽

Holger Vömel

Keyword(s):

Lower Stratosphere ◽

Temperature Measurements ◽

Climate Data ◽

Upper Troposphere ◽

Global Trend ◽

The Mean ◽

Temperature Climate

Abstract. Radiosonde observations (RAOBs) have provided the only long-term global in situ temperature measurements in the troposphere and lower stratosphere since 1958. In this study, we use consistently reprocessed Global Positioning System (GPS) radio occultation (RO) temperature data derived from the COSMIC and Metop-A/GRAS missions from 2006 to 2014 to characterize the inter-seasonal and interannual variability of temperature biases in the upper troposphere and lower stratosphere for different radiosonde sensor types. The results show that the temperature biases for different sensor types are mainly due to (i) uncorrected solar-zenith-angle-dependent errors and (ii) change of radiation correction. The mean radiosonde–RO global daytime temperature difference in the layer from 200 to 20 hPa for Vaisala RS92 is equal to 0.20 K. The corresponding difference is equal to −0.06 K for Sippican, 0.71 K for VIZ-B2, 0.66 K for Russian AVK-MRZ, and 0.18 K for Shanghai. The global daytime trend of differences for Vaisala RS92 and RO temperature at 50 hPa is equal to 0.07 K/5 yr. Although there still exist uncertainties for Vaisala RS92 temperature measurement over different geographical locations, the global trend of temperature differences between Vaisala RS92 and RO from June 2006 to April 2014 is within ±0.09 K/5 yr. Compared with Vaisala RS80, Vaisala RS90, and sondes from other manufacturers, the Vaisala RS92 seems to provide the most accurate RAOB temperature measurements, and these can potentially be used to construct long-term temperature climate data records (CDRs). Results from this study also demonstrate the feasibility of using RO data to correct RAOB temperature biases for different sensor types.

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Validation of Aqua satellite data in the upper troposphere and lower stratosphere with in situ aircraft instruments

Geophysical Research Letters ◽

10.1029/2004gl020730 ◽

2004 ◽

Vol 31 (22) ◽

Cited By ~ 74

Author(s):

A. Gettelman ◽

E. M. Weinstock ◽

E. J. Fetzer ◽

F. W. Irion ◽

A. Eldering ◽

...

Keyword(s):

Satellite Data ◽

Lower Stratosphere ◽

Upper Troposphere ◽

Aqua Satellite

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Sulfate geoengineering impact on methane transport and lifetime: results from the Geoengineering Model Intercomparison Project (GeoMIP)

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-11209-2017 ◽

2017 ◽

Vol 17 (18) ◽

pp. 11209-11226 ◽

Cited By ~ 12

Author(s):

Daniele Visioni ◽

Giovanni Pitari ◽

Valentina Aquila ◽

Simone Tilmes ◽

Irene Cionni ◽

...

Keyword(s):

Radiative Forcing ◽

Lower Stratosphere ◽

Stratospheric Ozone ◽

Radiation Absorption ◽

Coupled Models ◽

Upper Troposphere ◽

Aerosol Scattering ◽

Intercomparison Project ◽

Planetary Albedo ◽

The Tropics

Abstract. Sulfate geoengineering (SG), made by sustained injection of SO2 in the tropical lower stratosphere, may impact the CH4 abundance through several photochemical mechanisms affecting tropospheric OH and hence the methane lifetime. (a) The reflection of incoming solar radiation increases the planetary albedo and cools the surface, with a tropospheric H2O decrease. (b) The tropospheric UV budget is upset by the additional aerosol scattering and stratospheric ozone changes: the net effect is meridionally not uniform, with a net decrease in the tropics, thus producing less tropospheric O(1D). (c) The extratropical downwelling motion from the lower stratosphere tends to increase the sulfate aerosol surface area density available for heterogeneous chemical reactions in the mid-to-upper troposphere, thus reducing the amount of NOx and O3 production. (d) The tropical lower stratosphere is warmed by solar and planetary radiation absorption by the aerosols. The heating rate perturbation is highly latitude dependent, producing a stronger meridional component of the Brewer–Dobson circulation. The net effect on tropospheric OH due to the enhanced stratosphere–troposphere exchange may be positive or negative depending on the net result of different superimposed species perturbations (CH4, NOy, O3, SO4) in the extratropical upper troposphere and lower stratosphere (UTLS). In addition, the atmospheric stabilization resulting from the tropospheric cooling and lower stratospheric warming favors an additional decrease of the UTLS extratropical CH4 by lowering the horizontal eddy mixing. Two climate–chemistry coupled models are used to explore the above radiative, chemical and dynamical mechanisms affecting CH4 transport and lifetime (ULAQ-CCM and GEOSCCM). The CH4 lifetime may become significantly longer (by approximately 16 %) with a sustained injection of 8 Tg-SO2 yr−1 starting in the year 2020, which implies an increase of tropospheric CH4 (200 ppbv) and a positive indirect radiative forcing of sulfate geoengineering due to CH4 changes (+0.10 W m−2 in the 2040–2049 decade and +0.15 W m−2 in the 2060–2069 decade).

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Deriving an atmospheric budget of total organic bromine using airborne in situ measurements from the western Pacific area during SHIVA

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-6903-2014 ◽

2014 ◽

Vol 14 (13) ◽

pp. 6903-6923 ◽

Cited By ~ 41

Author(s):

S. Sala ◽

H. Bönisch ◽

T. Keber ◽

D. E. Oram ◽

G. Mills ◽

...

Keyword(s):

Stratospheric Ozone ◽

Radiative Heating ◽

Western Pacific ◽

Data Set ◽

Tropical Regions ◽

Upper Troposphere ◽

Tropical Tropopause ◽

Vertical Range ◽

The Western Pacific

Abstract. During the recent SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project an extensive data set of all halogen species relevant for the atmospheric budget of total organic bromine was collected in the western Pacific region using the Falcon aircraft operated by the German Aerospace agency DLR (Deutsches Zentrum für Luft- und Raumfahrt) covering a vertical range from the planetary boundary layer up to the ceiling altitude of the aircraft of 13 km. In total, more than 700 measurements were performed with the newly developed fully automated in situ instrument GHOST-MS (Gas chromatograph for the Observation of Tracers – coupled with a Mass Spectrometer) by the Goethe University of Frankfurt (GUF) and with the onboard whole-air sampler WASP with subsequent ground-based state-of-the-art GC / MS analysis by the University of East Anglia (UEA). Both instruments yield good agreement for all major (CHBr3 and CH2Br2) and minor (CH2BrCl, CHBrCl2 and CHBr2Cl) VSLS (very short-lived substances), at least at the level of their 2σ measurement uncertainties. In contrast to the suggestion that the western Pacific could be a region of strongly increased atmospheric VSLS abundance (Pyle et al., 2011), we found only in the upper troposphere a slightly enhanced amount of total organic bromine from VSLS relative to the levels reported in Montzka and Reimann et al. (2011) for other tropical regions. From the SHIVA observations in the upper troposphere, a budget for total organic bromine, including four halons (H-1301, H-1211, H-1202, H-2402), CH3Br and the VSLS, is derived for the level of zero radiative heating (LZRH), the input region for the tropical tropopause layer (TTL) and thus also for the stratosphere. With the exception of the two minor VSLS CHBrCl2 and CHBr2Cl, excellent agreement with the values reported in Montzka and Reimann et al. (2011) is found, while being slightly higher than previous studies from our group based on balloon-borne measurements.

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In situ detection of electrified aerosols in the upper troposphere and in the stratosphere

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-7061-2013 ◽

2013 ◽

Vol 13 (3) ◽

pp. 7061-7079 ◽

Cited By ~ 2

Author(s):

J.-B. Renard ◽

S. N. Tripathi ◽

M. Michael ◽

A. Rawal ◽

G. Berthet ◽

...

Keyword(s):

Lower Stratosphere ◽

Lower Troposphere ◽

Stratospheric Aerosol ◽

Balloon Flight ◽

Model Calculations ◽

Upper Troposphere ◽

Charged Aerosols ◽

In Situ Detection ◽

Aerosol Counter

Abstract. Electrified aerosols have been observed in the lower troposphere and in the mesosphere, but have never been detected in the stratosphere and upper troposphere. We present measurements of aerosols during a balloon flight to an altitude of ~24 km. The measurements were performed with an improved version of the STAC aerosol counter dedicated to the search for charged aerosols. It is found that most of the aerosols are charged in the upper troposphere for altitudes below 10 km and in the stratosphere for altitudes above 20 km. On the contrary, the aerosols seem to be uncharged between 10 km and 20 km. Model calculations are used to quantify the electrification of the aerosols with a stratospheric aerosol-ion model. The percentages of charged aerosols obtained with model calculations are in excellent agreement with the observations below 10 km and above 20 km. On the other hand, the model cannot reproduce the absence of detected electrification in the lower stratosphere, such that a distinct unknown process in this altitude range inhibits electrification. The presence of sporadic transient layers of electrified aerosol in the upper troposphere and in the stratosphere could have significant implications for sprite formation.

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Ozone variability and trends in the UTLS derived from the IAGOS- CARIBIC observatory using JETPAC

10.5194/egusphere-egu2020-7734 ◽

2020 ◽

Author(s):

Harald Boenisch ◽

Andreas Zahn ◽

Luis Millan

Keyword(s):

Water Vapour ◽

Lower Stratosphere ◽

In Situ Measurements ◽

Research Infrastructure ◽

European Research ◽

Coordinate Systems ◽

Upper Troposphere ◽

Work In Progress

The CARIBIC (Civil &#160;Aircraft &#160;for &#160;the &#160;Regular &#160;Investigation &#160;of the atmosphere Based on an&#160; Instrumented Container) project is part of the a European research infrastructure IAGOS (In- Service Aircraft for a Global Observing System) making regular in-situ measurements of more&#160; than 100 atmospheric constituents, include ozone and water vapour, on-board of an in-service&#160; passenger &#160;aircraft &#160;operated &#160;by &#160;Lufthansa. &#160;The &#160;dataset &#160;of &#160;the &#160;IAGOS-CARIBIC &#160;is &#160;therefore&#160; ideally suited as a testbed for the SPARC (Stratosphere-troposphere Processes And their Role&#160; in Climate) activity OCTAV-UTLS (Observed Composition Trends And Variability in the Upper&#160; Troposphere and Lower Stratosphere). One key aspect, shown here as work in progress, is to&#160; develop, define and apply common metrics for the comparison of different UTLS datasets&#160; using a variety of meteorological coordinate systems derived from reanalysis datasets. The&#160; focus here is on the variability of ozone in the upper troposphere and lower stratosphere&#160; (UTLS) on interannual and seasonal timescales and the observed trends. The in-situ ozone&#160; measurements by IAGOS-CARIBIC are analysed relative to different tropopause definitions&#160; and coordinate systems. All these meteorological information applied here are produced with&#160; the JETPAC tool &#8210; Jet and Tropopause Products for Analysis and Characterization (Manney et&#160; al., 2011).

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